TRENCH EXCAVATION AND BACKFILL

Transcription

1 SUDAS Standard Specifications Division 3 - Trench and Trenchless Construction Section Trench Excavation and Backfill TRENCH EXCAVATION AND BACKFILL PART - GENERAL.0 SECTION INCLUDES A. Trench Excavation for Pipe Systems B. Trench Foundation Stabilization C. Pipe Bedding and Backfill.02 DESCRIPTION OF WORK A. Excavate trench for pipe installation. B. Stabilize trench and install pipe bedding materials. C. Place backfill material in trench..03 SUBMITTALS Comply with Division - General Provisions and Covenants, as well as the following: A. Gradation reports for bedding materials. B. Results of required testing. C. Dewatering plan..04 SUBSTITUTIONS Comply with Division - General Provisions and Covenants..05 DELIVERY, STORAGE, AND HANDLING Comply with Division - General Provisions and Covenants..06 SCHEDULING AND CONFLICTS Comply with Division - General Provisions and Covenants..07 SPECIAL REQUIREMENTS None. Revised: 202 Edition

2 SUDAS Standard Specifications Division 3 - Trench and Trenchless Construction Section Trench Excavation and Backfill.08 MEASUREMENT AND PAYMENT A. General: The following items are incidental to the underground utility being installed and will not be paid for separately:. Standard trench excavation. 2. Removal and disposal of unsuitable backfill material encountered during standard trench excavation. 3. Removal of abandoned private utilities encountered during trench excavation. 4. Furnishing and placing granular bedding material. 5. Placing and compacting backfill material. 6. Dewatering. 7. Sheeting, shoring, and bracing. 8. Adjusting the moisture content of excavated backfill material to the range specified for placement and compaction. 9. Temporary support for existing water, sewer, gas, telephone, electric, and other utilities or services that cross the trench. B. Rock Excavation:. Measurement: Measurement will be by cubic yards of rock removed. 2. Payment: Payment will be at the unit price per cubic yard for the quantity of rock removed. C. Trench Foundation:. Measurement: Measurement will be in tons for the quantity of stabilization material required to replace material removed by over-excavation. Measurement will be based on the scale tickets for the material delivered and incorporated into the project. Trench foundation required to correct unauthorized over-excavation will not be measured. 2. Payment: Payment will be at the unit price per ton for the quantity of stabilization material furnished and placed. 3. Includes: Unit price includes, but is not limited to, removal and disposal of overexcavated material required to stabilize trench foundation; and furnishing, hauling, and placing stabilization material. D. Replacement of Unsuitable Backfill Material:. Measurement: Measurement will be in cubic yards for the quantity of backfill material required to replace unsuitable backfill material removed during standard trench excavation. Measurement will be based on compacted material in place. 2. Payment: Payment will be at the unit price per cubic yard for the quantity of backfill material furnished. 3. Includes: Unit price includes, but is not limited to, furnishing, hauling, and placing backfill material. 2 Revised: 202 Edition

3 SUDAS Standard Specifications Division 3 - Trench and Trenchless Construction Section Trench Excavation and Backfill.08 MEASUREMENT AND PAYMENT (Continued) E. Special Pipe Embedment or Encasement:. Measurement: Measurement will be by the linear foot along the centerline of pipe for each type of special embedment or encasement. 2. Payment: Payment will be at the unit price per linear foot for each type of special pipe embedment or encasement. 3. Includes: Unit price includes, but is not limited to, furnishing and placing all required special pipe embedment or encasement materials. F. Trench Compaction Testing: If the contract documents specify that the Contractor is responsible for trench compaction testing, measurement and payment will be as follows.. Measurement: Lump sum item; no measurement will be made. 2. Payment: Payment will be at the lump sum price for trench compaction testing. 3. Includes: Lump sum price includes, but is not limited to, all payments associated with retesting resulting from failure of initial tests. 3 Revised: 205 Edition

4 SUDAS Standard Specifications Division 3 - Trench and Trenchless Construction Section Trench Excavation and Backfill PART 2 - PRODUCTS 2.0 MATERIALS EXCAVATED FROM A TRENCH A. Standard Trench Excavation: All materials encountered during trench excavation, except rock and over-excavation.. Suitable Backfill Material: Class II, Class III, Class IVA, or Class IVB as defined in Section 300, Unsuitable Backfill Material: Includes, but is not limited to, the following materials: a. Soils not classified as suitable backfill material, as defined in Section 300, b. Individual stones or concrete chunks larger than 6 inches and averaging more than one per each cubic foot of soil. c. Frozen materials. d. Stumps, logs, branches, and brush. e. Trash, metal, or construction waste. f. Soil in clumps or clods larger than 6 inches, and without sufficient fine materials to fill voids during placement. g. Environmentally contaminated soils. h. Materials removed as rock excavation or over-excavation. 3. Topsoil: Class V material. Comply with Section 300, B. Rock Excavation: Boulders or sedimentary deposits that cannot be removed in trenches without continuous use of pneumatic tools or blasting. C. Over-excavation: Excavation of unsuitable or unstable material in trenches below the pipe zone, comply with Figure BEDDING MATERIAL A. Class I Material:. Crushed stone complying with the following gradation: Sieve Percent Passing / to 00 /2" 25 to 60 No. 4 0 to 0 No. 8 0 to 5 2. The Engineer may allow the use of gravel or authorize a change in gradation subject to materials available locally at the time of construction. 3. The Engineer may authorize the use of crushed PCC for pipe sizes up to 2 inches. 4. Use aggregates having a percentage of wear, Grading A or B, not exceeding 50%, determined according to AASHTO T Revised: 202 Edition

5 SUDAS Standard Specifications Division 3 - Trench and Trenchless Construction Section Trench Excavation and Backfill 2.03 BACKFILL MATERIAL A. Class II Material: Manufactured and non-manufactured open-graded (clean) or densegraded (clean) processed aggregate, clean sand, or coarse-grained natural soils (clean) with little or no fines. Class II materials are further described in Table Table 300.0: Class II Materials Type Coarse-Grained Soils, clean Coarse-Grained Soils, borderline clean to with fines Soil Group Symbol ASTM D 2487 GW GP SW SP e.g. GW-GC, SP-SM Description Well-graded gravels and gravel-sand mixtures; little or no fines. Poorly-graded gravels and gravelsand mixtures; little or no fines. Well-graded sands and gravelly sands; little or no fines. Poorly-graded sands and gravelly sands; little or no fines. Sands and gravels that are borderline between clean and with fines. Percentage Passing Sieve Sizes /2 in. No. 4 No % < 50% of "Coarse Fraction" > 50% of "Coarse Fraction" < 5% 00% Varies 5% to 2% B. Class III Material:. Natural coarse-grained soils with fines. Class III materials are further described in Table Do not use where water condition in trench may cause instability. Table : Class III Material Table Coarse-Grained Soils, with fines Soil Group Symbol ASTM D 2487 GM GC SM SC Description Silty gravels, gravel-sand-silt mixtures. Clayey gravels, gravel-sand-clay mixtures. Silty sands, sand-silt mixtures. Clayey sands, sand-clay mixtures. C. Class IVA Material:. Natural fine-grained inorganic soils. Class IVA materials are further described in Table The Engineer will determine if material is not suitable for use as backfill material under deep fills, surface applied wheel loads, heavy vibratory compactors, tampers, or other conditions. 3. Do not use where water conditions in trench may cause instability. 4. Material is suitable for use in dry trench conditions only. 5 Revised: 204 Edition

6 SUDAS Standard Specifications Division 3 - Trench and Trenchless Construction Section Trench Excavation and Backfill 2.03 BACKFILL MATERIAL (Continued) Table : Class IVA Material Type Fine-Grained Soils (inorganic) Soil Group Symbol ASTM D 2487 ML CL Description Inorganic silts and very fine sands, rock flour, silty or clayey fine sands, silts with slight plasticity. Inorganic clays of low to medium plasticity, gravelly clays, sandy clays, silty clay, lean clay. D. Class IVB Material:. Natural fine-grained inorganic (high elastic silts and plastic clays - fat clay) with a liquid limit greater than 50%. Class IVA materials are further described in Table When approved by the Engineer, material may be used as final trench backfill in a dry trench. 3. Do not use in the pipe embedment zone. Table : Class IVB Material Type Fine-Grained Soils (inorganic) Soil Group Symbol ASTM D 2487 MH CH Description Inorganic silts, micaceous or diatomaceous fine sandy or silty soils, elastic silts. Inorganic clays of high plasticity, fat clays TOPSOIL A. Class V Material:. Organic soils. Class V materials are further described in Table Use only as topsoil outside of the pavement, unless otherwise specified or allowed by the Engineer. 3. Do not use in the pipe embedment zone. Table : Class V Material Type Organic Soils (unsuitable for backfill) Highly Organic (unsuitable for backfill) Soil Group Symbol ASTM D 2487 OL OH PT Description Organic silts and organic silty clays of low plasticity. Organic clays of medium to high plasticity, organic silts. Peat and other high organic soils. 6 Revised: 204 Edition

7 SUDAS Standard Specifications Division 3 - Trench and Trenchless Construction Section Trench Excavation and Backfill 2.05 STABILIZATION (FOUNDATION) MATERIALS A. Clean 2 /2 inch crushed stone with the following gradation: Table : Stabilization Materials Sieve Percent Passing 2 / to 00 /2 35 to 70 0 to 20 /2 0 to 5 B. If specified, meet Iowa DOT Section 428 for Gradation No. 3 screened over a inch screen or the Engineer may authorize a change in gradation depending on materials available locally at time of construction. C. Crushed concrete may be used, if approved by the Engineer, if it is within + 5% of the gradation for each size of material SPECIAL PIPE EMBEDMENT AND ENCASEMENT MATERIAL A. Concrete Cradle, Arch, or Encasement: Use Iowa DOT Class C concrete. B. Flowable Mortar: Comply with Iowa DOT Article C. CLSM:. Approximate quantities per cubic yard: a. Cement: 50 pounds b. Fly ash: 250 pounds c. Fine aggregate: 2,90 pounds d. Water: 60 gallons 2. A compressive strength of at least 50 psi compressive strength at 28 calendar days can be expected. 3. Comply with material requirements of Iowa DOT Article Revised: 208 Edition

8 SUDAS Standard Specifications Division 3 - Trench and Trenchless Construction Section Trench Excavation and Backfill PART 3 - EXECUTION 3.0 TRENCH EXCAVATION A. Notify the Engineer prior to the start of excavation activities. B. Remove topsoil to a minimum depth of 2 inches and stockpile. C. Excavate trench to required elevations and dimensions. Comply with Figure Protect existing facilities, trees, and shrubs during trench excavation. 2. Place excavated material away from trench. 3. Grade spoil piles to drain. Do not allow spoil piles to obstruct drainage. D. Unsuitable Backfill Material:. If unsuitable backfill material is encountered, notify the Engineer. 2. Remove rock, rubbish, boulders, debris, and other unsuitable backfill materials at least 6 inches below and on each side of the pipe. 3. Keep unsuitable backfill material separated from suitable backfill material and topsoil. 4. Restore trench to design dimensions using bedding or stabilization material ROCK OR UNSTABLE SOILS IN TRENCH BOTTOM A. Notify the Engineer prior to over-excavation. B. The Engineer will determine the need for over-excavation and trench foundation stabilization prior to installation of pipes and structures. C. Comply with Figure for over-excavation of rock and wet or soft foundations TRENCH PROTECTION A. Install adequate trench protection (sheeting, shoring, and bracing) to prevent ground movement or damage to adjacent structures, pipelines, and utilities. B. Move trench boxes carefully to avoid disturbing pipe, bedding, or trench wall DEWATERING A. Maintain water levels below the bottom of trench excavation. B. Perform the dewatering operation according to the dewatering plan approved by the Engineer. The dewatering plan may be modified to meet actual field conditions, with approval of the Engineer. C. Ensure operation of the dewatering system does not damage adjoining structures and facilities. Cease dewatering operations and notify the Engineer if damage is observed. D. Discharged Water:. Do not discharge water into sanitary sewers. 2. Discharging water into storm sewers requires Engineer's approval. 8 Revised: 205 Edition

9 SUDAS Standard Specifications Division 3 - Trench and Trenchless Construction Section Trench Excavation and Backfill 3.04 DEWATERING (Continued) 3. Obtain permission of adjacent property owner prior to discharging water onto their property. 4. Maintain and control water discharge as necessary to prevent a safety hazard for vehicular and pedestrian traffic. 5. Direct water discharge away from electrical facilities or equipment. 6. Use dewatering equipment that will minimize disturbance from noise and fumes. 7. Protect discharge points from erosion. Provide sediment control for sediment contaminated water discharged directly from trench PIPE BEDDING AND BACKFILL A. General: Comply with Figures 300.0, , , , and , as appropriate.. Bedding and backfill used for pipe installation will depend on: a. Type of installation (water main, sanitary sewer gravity main, sanitary sewer force main, or storm sewer). b. Pipe material. c. Depth of bury. d. Pipe diameter. 2. After pipe installation, place remaining bedding material and immediately place backfill in trench. 3. Adjust the moisture content of excessively wet, but otherwise suitable, backfill material by spreading, turning, aerating, and otherwise working material as necessary to achieve required moisture range. 4. Adjust the moisture content of excessively dry, but otherwise suitable, backfill material by adding water, then turning, mixing, and otherwise blending the water uniformly throughout the material until the required moisture range is achieved. 5. Hydraulic compaction (flooding with water) is not allowed unless authorized by the Engineer. B. Pipe Bedding:. Granular Material: a. Class I granular bedding material is required for all gravity mains. Use when specified for pressure pipes. b. Comply with Figures 300.0, , , , and c. Place bedding material in the bottom of the trench in lifts no greater than 6 inches thick. Consolidate and moderately compact bedding material. d. Shape bedding material to evenly support pipe at the proper line and grade, with full contact under the bottom of the pipe. Excavate for pipe bells. e. Install pipe and system components. f. Place, consolidate, and moderately compact additional bedding material adjacent to the pipe to a depth equal to /6 the outside diameter of the pipe. 9 Revised: 205 Edition

10 SUDAS Standard Specifications Division 3 - Trench and Trenchless Construction Section Trench Excavation and Backfill 3.05 PIPE BEDDING AND BACKFILL (Continued) 2. Suitable Backfill Material: a. Only use with pressure pipe. Comply with Figure b. Use suitable backfill material to shape trench bottom to evenly support pipe at the proper line and grade, with full contact under the bottom of the pipe. Excavate for pipe bells. 3. Special Pipe Embedment and Encasement Materials: a. Concrete, Flowable Mortar, or CLSM: ) If specified in the contract documents, use concrete, flowable mortar, or CLSM in lieu of other bedding materials. 2) Secure pipe against displacement or flotation prior to placing concrete, flowable mortar, or CLSM. b. Waterstop: ) Place Class IVA clay backfill material, and compact to at least 90% of Standard Proctor Density. Obtain required compaction within a soil moisture range of optimum moisture to 4% above optimum moisture content. 2) If trench stabilization material is required, extend waterstop through stabilization material to bottom of trench. C. Haunch Support: Place from the top of the pipe bedding to the springline of the pipe.. Granular Material: a. Place Class I material in lifts no greater than 6 inches thick. b. Consolidate and moderately compact by slicing with a shovel or using other approved techniques. 2. Suitable Backfill Material: a. Place in lifts no greater than 6 inches thick. b. For Class II backfill material, consolidate and moderately compact by slicing with a shovel or using other approved techniques. c. For Class III and Class IVA backfill materials, compact to at least 90% of Standard Proctor Density. Obtain required compaction within a soil moisture range of optimum moisture to 4% above optimum moisture content. 3. Special Pipe Embedment and Encasement Materials: a. Concrete, Flowable Mortar, or CLSM: ) If specified in the contract documents, use concrete, flowable mortar, or CLSM in lieu of other bedding materials. 2) Secure pipe against displacement or flotation prior to placing concrete, flowable mortar, or CLSM. b. Waterstop: Place and compact Class IVA clay backfill material according to the suitable backfill material requirement above. D. Primary and Secondary Backfill:. General: a. For primary backfill, place from the springline of the pipe to the top of the pipe. b. For secondary backfill, place from the top of the pipe to foot above the top of the pipe. 2. Granular Material: a. Place in lifts no greater than 6 inches thick. b. Compact to at least 65% relative density. 0 Revised: 205 Edition

11 SUDAS Standard Specifications Division 3 - Trench and Trenchless Construction Section Trench Excavation and Backfill 3.05 PIPE BEDDING AND BACKFILL (Continued) 3. Suitable Backfill Material: a. Place in lifts no greater than 6 inches thick. b. For Class II backfill material, compact to at least 65% relative density. c. For Class III and Class IVA backfill materials, compact to at least 95% of Standard Proctor Density. Obtain required compaction within a soil moisture range of optimum moisture to 4% above optimum moisture content. 4. Special Pipe Embedment and Encasement Materials: a. Concrete, Flowable Mortar, or CLSM: ) If specified in the contract documents, use concrete, flowable mortar, or CLSM in lieu of other bedding materials. 2) Secure pipe against displacement or flotation prior to placing concrete, flowable mortar, or CLSM. b. Waterstop: Place and compact Class IVA clay backfill material according to the suitable backfill material requirement above. E. Final Trench Backfill:. Place suitable backfill material from foot above the top of the pipe to the top of the trench. a. Use no more than 8 inch thick lifts for backfill areas more than 3 feet below the bottom of pavement. b. Use no more than 6 inch thick lifts for backfill areas less than or equal to 3 feet below the bottom of pavement. 2. Place backfill material after recording locations of connections and appurtenances or at the Engineer s direction. 3. Class I and Class II Backfill Material: a. Compact to at least 65% relative density within right-of-way. b. Compact to at least 50% relative density outside right-of-way. 4. Class III and Class IVA Backfill Material: a. Compact to at least 95% of Standard Proctor Density within right-of-way. b. Compact to at least 90% of Standard Proctor Density outside right-of-way. c. Obtain required compaction within a soil moisture range of optimum moisture to 4% above optimum moisture content. 5. In areas to remain unpaved, terminate backfill material 8 inches below finished grade. Use topsoil for the final 8 inches above trench backfill material. 6. Terminate backfill material at subgrade elevation in areas to be paved TRENCH COMPACTION TESTING A. General: When trench compaction testing is specified in the contract documents as the Contractor s responsibility, provide testing of trench backfill material using the services of an independent testing laboratory approved by the Engineer. B. Soil Testing:. Cohesive Soils: a. Determine moisture-density relationships by ASTM D 698 (Standard Proctor). Perform at least one test for each type of cohesive soil used. b. Determine in-place density and moisture content. Use ASTM D 556 (sand-cone method) and ASTM D 226 (laboratory moisture content), or use ASTM D 6938 (nuclear methods for density and moisture content). Revised: 200 Edition

12 SUDAS Standard Specifications Division 3 - Trench and Trenchless Construction Section Trench Excavation and Backfill 3.06 TRENCH COMPACTION TESTING (Continued) 2. Cohesionless Soils: a. Determine maximum and minimum index density and calculate relative density using ASTM D 4253 and ASTM D b. For Class I granular bedding material, determine gradation according to ASTM C 36. C. Field Testing:. Testing Frequency and Locations: Perform testing of the final trench backfill, beginning at a depth of 2 feet above the top of the pipe, as follows: a. Coordinate the timing of testing with the Engineer. b. The Engineer will determine the location of testing. c. For each 2 vertical feet of consolidated fill, provide tests at a maximum horizontal spacing of 200 feet and at all street crossings. d. Additional testing may be required by the Engineer in the event of non-compliance or if conditions change. e. If necessary, excavate to the depth and size as required by the Engineer to allow compaction tests. Place backfill material and recompact. 2. Test Failure and Retesting: Rework, recompact, and retest as necessary until specified compaction and moisture content is achieved in all areas of the trench. In the event of failed tests, the Engineer may require retesting as deemed necessary. END OF SECTION 2 Revised: 200 Edition

13 Refer to the contract documents for specific material and placement requirements. Required only when specified in the contract documents or when directed by the Engineer. Key OD = Outside diameter of pipe D = Inside diameter of pipe TW = Trench width at top of pipe d = Depth of bedding material below pipe Bury Depth Final Trench Backfill TW OD 2'' min. Secondary Backfill OD/2 Primary Backfill Springline of Pipe D Haunch Support OD/2 REVISION FIGURE 300.0SHEET OF d OD/6 Pipe Bedding Over-excavation and Foundation Stone FIGURE STANDARD ROAD PLAN SW-0 SHEET of REVISIONS:Replaced Iowa DOT and SUDAS logos. SUDAS DIRECTOR DESIGN METHODS ENGINEER TRENCH BEDDING AND BACKFILL ZONES

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17 BEDDING CLASSES TW Place remainder of bedding and backfill materials as specified in the contract documents. 2 Minimum depth of bury 2 inches or as specified by the manufacturer. TW TW ALLOWABLE BEDDING CLASSES 2" PIPE MATERIAL STORM SEWER SANITARY SEWER Ductile Iron F-, F-2, F-3 F-, F-2, F-3 OD OD Class I Bedding Material OD HDPE Polypropylene F-2, F-3 F-2, F-3 Not allowed F-3 PVC F-2, F-3 F-3 4'' min. 4'' min. 4'' min. Key CLASS F- Class Bedding Material CLASS F-2 CLASS F-3 OD = Outside diameter of pipe 2 ALLOWABLE BURY DEPTH TW = Trench width at top of pipe: Min. = OD+8 inches OR.25xOD+2 inches (whichever is greater) PVC PIPE DUCTILE IRON, AWWA C5, CLASS 52 HDPE PIPE POLYPROPYLENE PIPE Pipe Diameter (in) ASTM D 3034 Solid Wall SDR 23.5 SDR 26 ASTM F 679 Solid Wall SDR 35 SDR 35 ASTM F 949 Corrug. Exterior ASTM F 803 Closed Profile ASTM D 2680 Composite (Truss Type) Pipe Diameter (in) 4 Class F- Class F-2 Bedding Bedding Class F-3 Bedding Pipe Diameter (in) 2 AASHTO M 294 8' Pipe Diameter (in) 2 ASTM F 2736 ASTM F ' 28' 32' 6 5 9' 5 25' ' 30' 28' 28' 32' 32' ' 9' ' 20' ' 28' 32' ' 3' 28' 37' 25' 34' 23' 32' 20' 29' 38' ' 9' 8' 8' 8' 8' * 48* 54* 60* 22' 22' 2' 22' 23' 2' 2' ' 23' 3' *Storm Sewer Only ' 22' 30' REVISION ' 2' 29' 48 6' 9' 27' 54 6' 9' 27' FIGURE STANDARD ROAD PLAN SW-03 SHEET of 60 REVISIONS:Added polypropylene pipe for storm sewer applications. SUDAS DIRECTOR DESIGN METHODS ENGINEER FLEXIBLE GRAVITY PIPE TRENCH BEDDING

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19 BEDDING CLASSES TW TW TW Class I Bedding Material OD OD OD d Loose, Suitable Backfill Material or Undisturbed Material with Bell Shaping d d CLASS P- CLASS P-2 CLASS P-3 DUCTILE IRON, AWWA C5, CLASS 52 ALLOWABLE BURY DEPTH PVC, AWWA C900 & C905, DR8 Place remainder of bedding and backfill material as specified in the contract documents. Pipe Diameter (inches) Class P- Bedding Class P-2 Bedding Class P-3 Bedding Pipe Diameter (inches) Class P- Bedding Class P-2 Bedding Class P-3 Bedding Key 4 4 9' 23' OD = Outside diameter of pipe ' ' 23' 9' 23' 9' 23' TW = Trench width at top of pipe: Min. = OD+8 inches OR.25xOD+2 inches (whichever is greater) ' 26' 23' 37' ' 23' 9' 23' 9' 23' d = Depth of bedding material below pipe: Min. = OD/8 OR 4 inches (whichever is greater) 8 20' 34' 8 9' 23' FIGURE SHEET OF ' 32' 6' 29' 3' 23' 3' 22' 3' 2' 3' 9' 3' 9' 38 3' 30' 29' 27' 27' ' 23' 9' 23' FIGURE STANDARD ROAD PLAN REVISION SW-04 SHEET of REVISIONS:Replaced Iowa DOT and SUDAS logos. SUDAS DIRECTOR DESIGN METHODS ENGINEER PRESSURE PIPE TRENCH BEDDING

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21 6'' min. 6'' min. 6'' min. 6'' min. 2 Place remainder of bedding and backfill material as specified in the contract documents. Place encasement material in two lifts, or as required to prevent pipe flotation. Allow previous lift to reach initial set prior to placing subsequent lifts. 2'' min. 6'' min. 3 Restrain pipe as necessary to prevent flotation. 2 Second Lift 3 2 Second Lift 4 When specified in the contract documents, install waterstops at a nominal spacing of 800 feet or at locations as specified by the Engineer. Springline of Pipe Springline of Pipe 2 First Lift 2 First Lift 4'' min. Flowable Mortar 6'' min. Class I Bedding Material PCC FLOWABLE MORTAR ENCASEMENT PCC ENCASEMENT A 5'-0'' Install compacted clay waterstop between pipe joints 2'' min. OD REVISION FIGURE SHEET OF A PROFILE WATERSTOP FOR TRENCHES 4 OD/8, 4'' min. SECTION A-A FIGURE STANDARD ROAD PLAN SW-05 SHEET of REVISIONS:Replaced Iowa DOT and SUDAS logos. SUDAS DIRECTOR DESIGN METHODS ENGINEER MISCELLANEOUS PIPE BEDDING

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23 A New Sewer Install pipe support for all new sewers 2 inches in diameter or larger when clearance between bottom of new sewer and top of existing line is 2 inches or less. Comply with Figure OD 2" or Less 2 " Compressible Material 2 Form interior surface of footings. Keep the 2 inch utility clear zone free of concrete. OD = Outside pipe diameter 2" Undisturbed Soil A 2 2 Bedding PCC 3" 2" Existing Utility (Sewer, Water, Gas, etc.) New Sewer 3" OD OD/4 FIGURE SHEET OF 2 " Compressible Material OD +6" SECTION A-A Existing Utility REVISION SHEET of SUDAS Standard Specifications SEWER PIPE SUPPORT OVER EXISTING UTILITY LINE

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25 REVISION Use reinforced concrete beam utility line support when new sewer excavation is crossing under an existing utility line (sewer lines, water lines, gas lines, etc.) as directed by the Engineer. Allow concrete to cure a minimum of 48 hours before placing backfill material. Existing Utility Line A Pipe Bell Special design required for trench width greater than 7 feet or trench depth greater than 5 feet. Sand (optional) Comply with Figure Concrete 3" 2" 2" 6" o.c. 2 bars min. New Sewer 3" 3" 8" 8" A Undisturbed Soil Hand place and carefully compact backfill material. Bedding Outside width of pipe bell, 2" min. SECTION A-A FIGURE SHEET OF SHEET of SUDAS Standard Specifications REINFORCED PCC BEAM UTILITY LINE SUPPORT

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27 REVISION Use flowable mortar utility line support when new utility excavation is crossing under an existing utility line (sewer lines, water lines, gas lines, etc.) as directed by the Engineer. Allow flowable mortar fill to cure a minimum of 24 hours before placing backfill material. Trim uncompacted backfill material away from slopes before pouring flowable mortar. Side slopes of flowable mortar fill to be : or greater. See Section A-A Comply with Figure Existing Utility Line A Place flowable mortar to springline of existing utility. FIGURE SHEET OF New Sewer A Bedding Undisturbed Soil Compacted Backfill SECTION A-A SHEET of SUDAS Standard Specifications FLOWABLE MORTAR FILL UTILITY LINE SUPPORT

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